The purpose of this study is to develop criteria for the comparative evaluation of member assistance programs (MAP's). These programs are a form of work-based peer intervention and support for deterring substance abuse and for motivating addicted workers to seek help and remain abstinent. In order to develop criteria for comparative evaluation, we propose to study two different MAP's within the transportation industry: the railroad industry's Operation Redblock Program, and the airline industry's Association of Flight Attendants EAP. Through the use of qualitative methods of data collection (i.e., in-depth interviews, participant observation and document analysis) and analysis (i.e., the constant comparative method) we will generate "thick descriptions" and "grounded hypotheses about how peer influence deters substance abuse among coworkers, motivates addicted workers to seek help, and assists addicted workers in remaining abstinent? These methods will also help us to uncover how these peer influence processes vary according to: (a) client and peer gender, race and age, (b) the type of substance being abused (i.e., alcohol or other drugs), and (c) occupation and work context.